1264158640 has 20 divisors (see below), whose sum is σ = 2939169024. Its totient is φ = 505663424.

The previous prime is 1264158601. The next prime is 1264158647. The reversal of 1264158640 is 468514621.

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 1264158640.

It is not an unprimeable number, because it can be changed into a prime (1264158647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7900912 + ... + 7901071.

Almost surely, 2^1264158640 is an apocalyptic number.

1264158640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1264158640 is an abundant number, since it is smaller than the sum of its proper divisors (1675010384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1264158640 is a wasteful number, since it uses less digits than its factorization.

1264158640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15801996 (or 15801990 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 1264158640 is about 35555.0086485716. The cubic root of 1264158640 is about 1081.2692667443.

The spelling of 1264158640 in words is "one billion, two hundred sixty-four million, one hundred fifty-eight thousand, six hundred forty".